Adjustable linkage for dental chairs and the like



D. J. BINUS 2,517,831

ADJUSTABLE LINKAGE FOR DENTAL CHAIRS AND THE LIKE Aug. 8, 1950 E 3 Sheets-Sheet 1 INVENTOR.

ATTORNEY$ Aug. 8, 1950 J, us 2,517,831

ADJUSTABLE LINKAGE FOR DENTAL CHAIRS AND THE LIKE Filed July 1, 1946 3 Sheets-Sheet 2 \k 1\ 1] 6 H gr-134 Ill-3 140 12 I 1 22 2 I 0 'M :(30 111-2 f 112 129 O- O f 119 1/45 1 [Z8 I31 INVEN TOR.

BY Davz'a'J Bin as #MM 91% ATTORNEYS Aug. 8, 1950 D. J. BINUS ADJUSTABLE LINKAGE FOR DENTAL CHAIRS AND THE LIKE Filed July 1 1946 3 Sheets-Sheet 5 INVENTORY ATTORNEYS Patented Aug. 8, 1 950 untranrmss. PATENT ()F-FlCE 'ADJUSTABLELINKAGE FOR'DENTAL cnarasnnn THE LIKE- DavideJnBinusa Canton, Ohio, assignorsto -Tlle ton, Ohio, anorporation of'Dhid.

Weber, Dental. Manufacturing Company, Can- Applicationiuly 1; 1946, Serial No. 680,755

adjustable linkage may :be secured on the-top of 15.

theiupper extensiblwmembei ot the-usual 'rja'ck of a. dentat chain; and' one efthe-bars -may--' provide acsupport tor the seat-frame of the chair and the pivotal connection'betweenthe ack supported an A and theseat frame supporting bar havinga hurt about whicmmy desired tilt relative to thehorizontalsis given to-theseat irame:

In-suel1 -seattiltinglinkages on usual dental chairs prior to the present improvements, com

siderable diflicu-lty has been encountered-in providingifor -tlie' ad-j ustment of the linkage whereby" the endsof the jack-supported link bar and the seatsupporting link bar not =p-ivotally-connected witheachother are swung towards and" away from-each-otherand locked at any-desired position-relativetoeaeh -cther-by the remaining--ad= justable link bar means of'the linkage.

The adjustable link bar means -for such usual seat tilting-- linkagesfor -dental chairs have in-- cludeda'- relativel large number'of' parts; with which considerable difficulties-are encountered inmanufacture and'assembly, and whicharejinconvenient td operate; One such-usual adjustable link bar mreansfora dental chair-linkaga'with whichthe above enumerated difliculties have been; encountered; includes a-' plurality of flat plates or discs ineluded as part of one-otthepivotal 'connections and between-which-extends a pluralityofi-ilat platesmr'leaves included a's'part of one of the bars;= tcgether with means for clamping the interposed plates-against each other;

In such an adjustable link bar meansgthe multiplicity of the interposed fiat plates results in relatively expensive manufacture and assembly, as well as inconvenient operation,

Themultiple interposed fiat plates with clamp.- ingmeans previously :used in. adjustableJink-bar means ion-usuatseat.tiltinglinkages for dental chairs aresupcriol' in clamping action than am 55;.

other type of adjustable link bar means in which;v

oneoi the link; barsis'a slide bar usually cylindric and which slidesqin-i a fitting :sleeve pivotedin aplane containing the longitudinalaxis of the slide bar,- andvthere-ibeing:clampingscrew .means operating: to efieotzai clamping action between-the sleevenanmthe slide ban-also inaplane contain-.-

ing the longitudinal axis of the slidezcbari This.

clampin action; operatingl between; the i. pivot sleeve and the slide bar in a planecontaining the,

longitudinal axiswictheislide bar. is not as efiective as the interposed palates; clampedlagainstseach.

othen andmereoverlfreqnently slips under loadf'a The; 0bient's:ofz the present; invention. include. thei=provisionoot ancimproved adjustable linkage paalticularlyiadaptedzior use. in a dental chair and;

the like, and which is simplified in construction ands-inn thee arrangement and: cooperation. of J its parts, and particularly withrespect to its-ad justable linkzsbar means, so thatior each ofi the separate parts the required fabricating operations mayi-be accomplished. largely by rotary machining I andgrinding operations.

Eurthenobje'cts-ofthe present invention includetheprovision of such an improved adjustable linkagein which quick and easy adjustments may be-made.-in its adjustable link bar means, and iriwwhich a very" tight lacking or clamping may be efiected between the adjusted parts.

Further objects oi the present invention include the provisicn in an -adjustable linkage of clamping means operative in combination with a link bar to-pruvide-a variable distance between two of the pivotal connections ofthe linkage, and of such nature that when one of the link barsof the linkage has a load applied thereto, the clamping action. increases cumulatively as the load increases.

. The foregoing and-other objects-areattained by the adjustable linkage, adjustable link bar means,

parts, combinations, and sub-combinations which gether. with-their modeofuse are set forth in the following description, and which are particularlyand distinctly poi-nted-out and set forth in-the' appended claim iorming part hereof.

The nature of the present invention may be stated in general terms as including in an adjustable linkage for-a dental chair andth'elike, a pin-- rality. of link: bars,v pivotal connections between. some of: the: link .bars, and some of the link barsbeing each included in two ot the pivotal eonnection's, two of thelink bars each being included; in only one of the pivotal connections and constituting parts of an adjustable link bar means, the adjustable link bar means including in addition to the pivotal connection in which each of its two link bars are included, a slide bearing aperture in one of the link bars of the adjustable link bar means and a portion of the other link bar of the adjustable link bar means being shaped to slidably fit in the slide bearing aperture, and the slide bearing aperture being ofiset from the pivotal connection of the link bar in which it is included, and means for clamping the relatively slidable link bars so as to secure them at any desired position of adjustment.

By way of example, embodiments of the improved adjustable linkages' of the present invention are illustrated in the accompanying drawings forming part hereof, in which Figure 1 is a top plan view of one of the improved linkages, with portions broken away;

Fig. 2 is a side elevation thereof looking in the direction of the arrows 2-2, Fig. 1;

Fig. 3 is an end elevation thereof looking in the direction of the arrows 3-3, Fig. 2;

Fig. 4 is a top plan view of the seat frame of a dental chair included as part of one of the improved adjustable linkages, mounted on the top -of the upper lifting member of a usual dental chair elevator;

Fig. 5 is a fragmentary sectional view thereof as on line 5-5, Fig. 4;

Fig. 6 is another fragmentary sectional view thereof as on line 6-6, Fig. 4;

Fig. 7 is a fragmentary side elevation of a dental chair including another embodiment of the improved adjustable linkage hereof for adjustably tilting the dental chair back with reference to its seat frame; and

8 is a'fragmentary sectional view thereof as on line 8-8, Fig. 7.

Similar numerals refer to similar parts throughout the drawings.

One embodiment of the improved adjustable linkage of the present invention is illustrated in Figs. 1, 2, and 3, and indicated generally by ID, and includes a first link bar indicated generally by H, which as shown is of plural member construction and includes two laterally spaced longitudinally extending bar members 12a and 12b which are preferably parallel with each other and may be secured in spaced relationship with each other as by longitudinally spaced shouldered rivet studs I3.

The adjustable linkage l0 furthermore includes a second link bar indicated generally by l4, which as shown includes one longitudinally extendin straight portion I4-l which is angled at a central bend l4-2 with respect to a second longitudinally extending straight portion l4-3. The straight portion 1-1 of the link bar I as shown is located above and is parallel with the bar members 42a and l2b of the first link bar II. The other straight portion l4-3 of the link bar [4 inclines downwardly from the bend l4-2 and extends between the bar members 12a and 12b adjacent one end 45 of the link bar II, where the end of the straight portion l4-3 of the link bar I4 is provided with an enlarged pivot bearing head 46 having a central bore, horizontal as shown, which registers with similar bores provided in the bar members 42a and I2b. A pivot pin I1 extends through the registering bores in the bar members l2a and 42b and the intervening pivot bearing head [5, and provides therewith a pivotal connection between the link bar H and the link bar I4.

Above the other end l8 of the link bar H, the outer end of the straight portion l4-l of the link bar 14, as shown, is formed to constitute part of another pivotal connection in the linkage [0, as by providing an outwardly opening U pivot bearing head l9.

The adjustable linkage I0 furthermore includes a third link bar indicated generally by 20, and which, as shown and preferably for certain purposes of the present improvements, is in the form of a longitudinally extending cylindric rod, the upper end of which is shaped as a pivot bearing head 2| having opposite fiat faces 22 fitting between the inner opposite faces of the U pivot bearing head 19 of the second link bar I4. The pivot heads 2! and i3 have formed therein registering bores in which is fitted a pivot pin 23, and the construction including the pivot heads 19 and 2| and pivot pin 23 constitutes another pivotal connection in the linkage ID.

The adjustable linkage l0 furthermore includes a fourth link bar indicated generally by 24, which as shown, and preferably for the purposes of the present improvements, is in the form of a U clamp link bar having an outer base portion 24-l from which extend U leg portions 24-2 and 24-3, which are located between the bar members [2a and [2b at the end [8 of the link bar H.

The base portion 24-l of the U clamp link bar 24 has formed therein as shown a cylindric slide bearing bore 25 which communicates at one side with the opening 26 between the U leg portions 24-2 and 24-3, and the cylindric rod link bar 20 fits in and entends through the bore 25 beyond the end 48 of the link bar II.

The U leg portions 24-2 of the U clamp link bar 24 has formed therein a pivot bearing bore 21, and the bar member i2a of the link bar H has formed therein an enlarged pivot bearing bore 28 axially aligned with the pivot bearing bore 21. A pivot stud 29 has a cylindric shank 30 fitting in the bearing bore 21 and an enlarged cylindric head 3| fitting in the bearing bore 28. There is thus formed a pivotal connection between the U clamp link bar 24 and the link bar H.

The slide bearing bore 25 and the pivot bearing bore 2'! are thus offset from each other in the U clamp link bar 24, and this relationship constitutes an important feature of the invention.

.For the purpose of providing an adjustable and releasable clamping or locking between the U clamp link bar 24 and the cylindric slide rod link bar 20, the bar member [21) of the link bar H has formed therein an internally threaded bore 32 which is opposite the adjacent outer face of the U leg portion 24-3 of the U clamp link bar 24. Preferably as shown the threaded bore 32 is axially aligned with the bores 21 and 28. An externally threaded clamp screw 33 is screwed in the internally threaded bore 32 and has an inner reduced clamping head 34 abutting against the adjacent outer face of the U leg portion 24-3 of the U clamp link bar 24. The outer end of the clamp screw 33 as shown is formed as a square head 35 for permitting easy rotation of the clamp screw 33 by a wrench. When desired a lever handle may be secured on the outer end of the clamp screw 33.

For maintaining alignment of the slide rod link bar 20 when the u clamp link bar 24 is released, there is provided on the U clamp link bar 24 a bowed fiat leaf spring 36 whose central portion is secured to the outer face of the base portion 24-l of the U clamp link bar 24, the

.ends of the leaf spring 36 extending in opposite diifeetins fromthabase-portion'l k-I and press ing against the outer 'sideof the'slide rod' lifik rga n. v, In the operation of the improvedadjustahly linkage "I-Il} when the clamping screw- -3 this-turned so that its clam ping head 34 -moves-in the-'diree=- tibn away from the U leg 'portion Z P-4 o? the U "clamp "linkbar 24, the-clamping pressure of: L the'flclamp'linkbar Zton the c-yl-in'di'imslide rod'link bar-QWisreIeased, and the slideaod link bar-2fi is free to slidei-n either direction through the-bore 2 5 01 *the- U clamp 24- thereby permitting swinging (in-the second link'bar' H ontl'iepivot-pirr'll up 01" downas viewed: in -the drawing. I v H The slide rod link bar 28 and the U clampiink barflasthus'assoeiated with-each wher -maybe considered adj ustable link banmeans-having two pivotaiconnections onewith thefirst link har fl and the othei withtheficond link bar Hf and 29- the linkage I 9 may-be 'consideredin one sens'e as a-three' barIin-kager However; in anothersense the adjustable linkage-I 9"-may-'aiso-be-con sidered as" a four bar" linkage withoufipivotai connection between theslide'rodlink b'ar zli-andi the Unlamplink-bar-Zd? Considered as a unitary-adiustdble flirik bar} meansor-assembly', it-is-obvious that -tlre' comm nation of the-"slide rod lil'rk' bar" 2? and th U clamp link barZdmaybensedzas an amend-meat link bar-unit-in arradjustabie'iirrkage havingany desired"rrumb'er-oflink ban-units."

'Moreover, the particular" combination off the oppositefispaced barmembers I Z'wa'nd I227? the mounting "ofthe U clamp lin'kbar' 2 4 therelie tween at theend" I3? and theclamp-screw 33 constitutes 'in' itself-an improved prvot vis'e" par= ticu'larly adapted for releasably'clampmgeandf holding the rod 'AIi or similar piece'fat any'de f sired"angle""over'"awide 'rangedthtrespect wthe longitudinahaxtspf the bait membersf lliz f and..I2b.

The'objects oftheinvention are thus attained by the construction and arrangement of the H adjustable linkage I as above described, and asillus tra-ted; and which are particularly adapted for the performance of the greater. number of machining grindingroperations-z onr'the several parts by the use of rotary machine tools. Also. the easy and rapid assembly ofthe improved linkagalfi is attained, and its operation iseasy andqui'ck' in efiecting release or'locking of f' the U clamp link bar 23 on the slide rod link baa-20'.

Moreover, offsetting the cylindric slide bearing bore 25 for the cylindric rod link bar 28 irom. thercommon axis of the pivot bearing bore 21 and the clamping screw 33 produces a binding or cooking of the U clamp link bar 24 on the slide rod link bar 29, when for example the link bar II is a base such as when supported on the top of the upper member of a dental chair elevator, and when the link bar I4 is loaded such as when it supports or is a part of a dental chair seat frame.

In Figs. 4 to 6 inclusive is illustrated a second embodiment I II) of the improved adjustable linkage mounted on the top of the upper lifting member I40 of a usual dental chair elevator, not otherwise shown.

In the linkage III), the first link bar indicated generally by III is in the form of a one-piece generally triangular cast member secured on the top of the upper lifting member I40 of the dental chair elevator. The second link bar indicated 7 generallyzbyv-ilfl thezfo'rmzof a dental: chairs seat frame-cast asaai one piecezsmemltern- 1 The 'triangiilarv'oneepiece bar l Uhhas, at opposite ends of its 'base' :portiom 'I I'l 1i-oni axi common horizontal axis-indicated: bytthe dot? dash line I I I -'-2- and.whichsintersects ati I I ia- 3; the vertical axis-"of movement of the elevators upper lifting member-ildflintwo opposite outawardly. extending pivottrun'nions-z I1 1 eachipof; which'pivots in bearing 'means l I 4-x-4 011 ."theise'atl frame' link ban-114v" :The'first linkzbar IH :and-i the second link bar I I I thus: have-coaxial ipivh otal connec'tiens w ith'eaohother; From the front :side I I4-"-'-5.ioi3rthe seat. frames link bar I l'fl 'extends. rearwardly; a; rearwardlyl opening U' pivot-bearing head II 9;v .A third cylin' dric rod link bar= IZU' ha's an:upper pivot-bear ing head I 2 I l extending 'withvclearancebetween 1 the inner opposite faces; of the u pivot: bearing head I'IS of -the secondaIink "banLMi The pivot: heads I 2-I and H 9- have formed thereirr'registereing bores in which is 'fitted apivot pin I231 There) is thus provided a pivotal Ic'onnection between. the. second link bar "-'I I tend the third linkcbar. I202- -A fourth ilinir bar indicated generallywby tfl hasa constructionsir'nilar to tlFie U' clamp link bar 243 and; a similar arrangement with the oyliiri drioslide rod i link liiain led-1 bearing bore the pivot bearing bore I21 in -the-- U leg portioir= lzwz or tue ueiamnmnee e124w 1 e-nrstumkmemoee l mn saormed tuereim on opposite side s ofi' the US clamp link bar" 'I 21? upstanding l'aterally' spaced 'lugs 'l I20 and H255 ln -the lug me there i's -formed an' en larged pivot bearing bore I28 axially a lignedl with the 'pivot baring bbre 121; A ivot stud I29'- has-a cylindrical shank ISO fittingin: the bearingbore I2'I"{andanenlarged cylindri'chead I3'I fitting m= the'-bearing-bore- I28; There is thus formed a" pivotal connection between the U clamp-link bar I24- a'-nd"the="1ink'bar= III-E The lug 'l l2b'"on the link bar III has formed= therein an internally threaded bore I32 which is opposite the; adjacent outeriace of the U leg portion I2 I-- 3 of the u clamp link bar- I24: Preferably as shown the threaded bore I32 is= axially aligned with the bores I21 and I 28; An

externally threaded clamp screw I33-is screwed 50 in theinternally threaded-boraIiiZ and hasan inner; reduced clamping head I34 abuttingagainst the adjacent outer face of the U leg: portion I24-3 of the U clamp link bar I24. Extending laterally'beyond its'threaded portion and away fromthe lug IIZh-the-clamp screw-I33 has a cylindric shank 'I33I. Laterally' offset from the lug II 22); the link-bar I I I has an upstanding bearing block I33-2 with a bearing bore therein through which the shank I33I extends and fits.

The seat frame link bar H4 engirdles a relatively large frame opening II46, and the outer end of the shank I33--I is located above the opening II46, and the outer end of the shank I33I has secured thereon the upper end of an operating lever MI which extends downwardly through the opening 4-6 and is curved outwardly and terminates in a foot pedal I4II at one side of the seat frame link bar H4. Above the clamp screw shank I33--I the lever MI is provided with upwardly extending laterally spaced lugs I4I2. The link bar III is provided with an upwardly extending guide block I42 having a guide bore I43 formed therein and extending at right angles with the pivot axis III-2, and the guide tore I43 is aligned with the space between the laterally spaced lugs I4I-2.

A guide shaft I45 has a pivotal connection between its forward end and the lugs I4I-2, as by means of a pivot pin extending through registering bores in the lugs I4I--2 and the intervening end of the guide shaft I45. The rear end of the guide shaft I45 extends slidably with clearance through the bore I43 in the block I42. Intermediate the ends of the guide shaft I45 there are formed thereon external threads I46 on which is screwed an adjusting nut I41, and a helical compression spring I48 extends around the shaft I45 and is interposed between the nut I41 and the opposite face of the block I42. The compression spring urges the shaft I45 away from the block I42, and forwardly towards the front of the seat frame link bar H4.

The lever lugs I4I2 pivotally connected with the shaft I45 are thus urged forwardly and the clamp screw I33 is urged in a counter clockwise direction as viewed in Fig. 6. The threads on the clamping screw are preferably right hand threads, and the clamping screw I33 is thus urged to maintain a clamping and locking pressure on the U clamp link bar I24 and thus on the slide rod link bar I20 thereby serving to automatically maintain the seat frame link bar I I4 at any particular' tilted position with respect to the horizontal base link bar III.

For changing this tilt, the operator depresses the pedal I4I--I and thus the lever I4I, and releases the clamping pressure of the screw I33 on the U clamp link bar I24, and permits tilting the seat frame link bar I I4 to any other desired position. I

In Figs. 7 and 8 a dental chair indicated gen- 'erally by 2I0 includes another embodiment of the improved adjustable linkage hereof for adjustably tilting the dental chair back with reference to its seat frame. In this embodiment of the improvements, the first link bar is constituted by the one-piece back 2I I, the second link bar is constituted by the seat frame 2I4, the third link bar is constituted by the slide rod 220, the

fourth link bar is constituted by aback tilting lock block 224--I, and the fifth link bar is constituted by the U clamp 224, and these link bars are pivotally connected with each other in a manner similar to the embodiments I and III], and the U clamp link bar is operated by a spring pressed lever 24I, similar to the spring pressed lever MI in the embodiment IIG. In the embodiment 2I0 any desired tilt of the one-piece back link bar 2 is attained by actuation of the lever 24I, and it is to be noted that the clamping action of the U clamp link bar 224 operates two 5 Number ways and when the linkage is the clamped condition the slide rod link bar 220 can slide neither up nor down, which is a distinct advantage in use. v

The embodiments of the present improvements illustrated and described herein are by way of example, and the scope of the present invention is not limited to the same or to the particular details thereof but is commensurate with any and all novel subject matter contained herein which may at any time properly under the patent laws be set forth in the claim hereof or originating herein, and the elements of any such claim are intended to include their reasonable mechanical and functional equivalents.

I claim:

In adjustable linkage apparatus, a U clamp link bar, the U clamp link bar including a base portion and oppositely spaced U leg portions extending from the base portion, two members secured in opposite spaced relation with each other, the U leg portions extending between the spaced members, pivotal connecting means between one of the spaced members and one of the U leg portions, a slide link bar extending through the opening between the. spaced U leg portions of the U clamp link bar and between its base portion and thepivotal connecting means, and means operatively mounted on the other spaced member for varying by the application of pressure on the U leg portions the distance between the U leg portions of the U clamp link bar, and the base portion of the U clamp member having a slide bearing opening communicating at one side with the opening between the U leg portions, and the slide link bar slidably fitting and extending through the slide bearing opening, and an elongated leaf spring having its central portion secured on the outside of the base portion of the U clamp memher and having ends on opposite sides of the U clamp member in spring abutment against a side of the slide link bar.

DAVID J BINUS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Mosher May 9, 1899 Bartholomew Jan. 25, 1910 Arens Dec. 4, 1945 FOREIGN PATENTS Country Date France May 3, 1932 Number 

